Nanometer level fabrication sizes are required in the manufacture of semiconductor devices that are increasingly miniaturized. New techniques that replace photolithography are needed to meet the requirement.
Self-assembly lithography is drawing attention as one such technique. The self-assembly lithography is a method of forming a micropattern as follows: A fabrication target film is coated with a block copolymer that constitutes a nano-order rule structure, and the block copolymer is then phase-separated. One block is removed, and the other block is used as a mask to fabricate the fabrication target film.
A directed self-assembly (DSA) technique has been developed as a method of controlling the directionality of a natural regular pattern. According to this technique, a guide pattern is formed on a fabrication target film by photolithography. The guide pattern is coated with a block copolymer, and an artificial order is thereby given to the natural phenomenon pattern.
However, it has been difficult to accurately form micro hole patterns even by the use of the DSA technique.